Vitamin C Benefits
Smokers may benefit from a higher intake. Dr. Weil recommends taking 250 mg of vitamin C each day.
How much does a child need?
NIH recommends Adequate Intakes (AIs):
- infants 0-6 months old, 40 mg per day
- infants 7-12 months old, 50 mg per day.
The RDAs of vitamin C for teens and children are:
- toddlers 1-3 years old, 15 mg per day
- children 4-8 years old, 25 mg per day
- children 9-13 years old, 45 mg per day
- male teens 14-18 years old, 75 mg per day
- female teens 14-18 years old, 65 mg per day
How do you get enough vitamin C from foods?
Vitamin C is easy to get through foods, as many fruits and vegetables contain vitamin C. Good sources include: apples, asparagus, berries, broccoli, cabbage, melon (cantaloupe, honeydew, watermelon), cauliflower, citrus fruits (lemons, limes, oranges), kiwi, fortified foods (breads, grains, cereal), dark leafy greens (kale, spinach), peppers (especially red bell peppers, which have among the highest per-serving vitamin C content), potatoes, and tomatoes.
Are there any risks associated with too much vitamin C?
When obtained from food sources and supplements in the recommended dosages, vitamin C is generally regarded as safe. Side effects are rarely reported, but include diarrhea, nausea, abdominal cramps, and other gastrointestinal symptoms. For most healthy individuals, the body can only hold and use about 200-250 mg of vitamin C a day, and any excess is lost though urine. At times of illness, during recovery from injury, or under conditions of increased oxidative stress (including smoking), the body can use greater amounts. High doses of vitamin C (greater than 2,000 mg/day) may contribute to the formation of kidney stones, as well as cause severe diarrhea, nausea, and gastritis.
Are there any other special considerations?
Adverse affects may occur between vitamin C and anticoagulant drugs such as warfarin (Coumadin), decreasing their action. Nicotine products, oral contraceptives/estrogens, tetracyclines, barbiturates, and aspirin may decrease levels of vitamin C.
Vitamin C may increase absorption of iron and lutein. Although some evidence suggests that large doses of supplemental vitamin C may interfere with the absorption and metabolism of vitamin B12 found in food, other studies have shown no such effects.
Updated by: Andrew Weil, M.D., and Brian Becker, M.D., on Oct. 29th, 2012
Reviewed by Benjamin S. Gonzalez, M.D., May, 2016.